1. Field of the Invention
The present invention relates to hybrid polypeptides having cellobiohydrolase activity, polynucleotides encoding the hybrid polypeptides, methods of producing the hybrid polypeptides, and methods of using the hybrid polypeptides.
2. Description of the Related Art
Cellulose is a polymer of the simple sugar glucose covalently linked by beta-1,4-bonds. Many microorganisms produce enzymes that hydrolyze beta-linked glucans. These enzymes include endoglucanases, cellobiohydrolases, and beta-glucosidases. Endoglucanases digest the cellulose polymer at random locations, opening it to attack by cellobiohydrolases. Cellobiohydrolases sequentially release molecules of cellobiose from the ends of the cellulose polymer. Cellobiose is a water-soluble beta-1,4-linked dimer of glucose. Beta-glucosidases hydrolyze cellobiose to glucose.
The conversion of lignocellulosic feedstocks into ethanol has the advantages of the ready availability of large amounts of feedstock, the desirability of avoiding burning or land filling the materials, and the cleanliness of the ethanol fuel. Wood, agricultural residues, herbaceous crops, and municipal solid wastes have been considered as feedstocks for ethanol production. These materials primarily consist of cellulose, hemicellulose, and lignin. Once the lignocellulose is converted to fermentable sugars, e.g., glucose, the fermentable sugars can easily be fermented by yeast into ethanol.
There is a need in the art for new enzymes to increase efficiency and to provide cost-effective enzyme solutions for saccharification of cellulosic material.
WO 2010/060056 discloses a hybrid polypeptide composed of a Talaromyces emersonii cellobiohydrolase I and a Trichoderma reesei cellobiohydrolase I carbohydrate binding domain.
The present invention provides hybrid polypeptides having cellobiohydrolase activity.